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Hi,

I've been struggling with my clarinet's left hand side C key. When I use it to play a C it chokes the sound but sometimes it works fine. I feel that there's some backlash when pressing the key. So far I've oiled the keywork and added some spring tension to the left hand C's spring. None of those things have helped.

I wonder if there's a piece of cork missing somewhere or something else that would explain this behaviour.

View attachment 218544

Should there be a gap like this? The upper "jaw" has some cork on it but the lower one does not. Btw. Clarinet is a Yamaha YCL-650 (about 2 years old).

Thanks!
-TH
 

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It is hard to tell in the photo, but the upper part of the key mechanism appears to have a thin "tech cork" glued to the surface---probably for quieting. The problem with tech cork is that it produces a lot of friction. The lower part of the mechanism also needs to be rounded more where it comes in contact so there is a better sliding motion. I would recommend replacing the tech cork with thin synthetic felt, and filing/sanding/buffing the lower part to have a rounded top corner. Yamaha is generally quite good when it comes to design, but this particular key mechanism seems to have been "under engineered". :)
 

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Alto sax, Tenor sax, Clarinet
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Hi,

I've been struggling with my clarinet's left hand side C key. When I use it to play a C it chokes the sound but sometimes it works fine. I feel that there's some backlash when pressing the key. So far I've oiled the keywork and added some spring tension to the left hand C's spring. None of those things have helped.

I wonder if there's a piece of cork missing somewhere or something else that would explain this behaviour.-TH

Normally the upper piece that you show has the cork, but the lower part that rocks up to close the C does not have any cork so that a moving contact between the two can be smooth. I agree that it sounds like a leak, and you should have a qualified tech check it out.
 

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I find that when I haven't played in while my left ring finger will slide off the hole just enough to create a leak when I use the left hand C key. Could be?
 

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I agree with AddictedToSax. If you're pressing the touch plate to where it stops, and the RH C works, the keywork probably isn't the issue. I tend to do that with LH B if I'm not careful as while I've got big hands, I've got a proportionately short little finger.
 

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Might be that one of the pivot screws loosened up just enough so that the travel of the key rod is a bit off. Have it checked out if you can’t DIY.
 

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I wonder if there's a piece of cork missing somewhere or something else that would explain this behaviour.
Yup!
The connection shown in your photo easily goes bad if the cork is a little off. Mine just fell off entirely, causing the key too stick on the leftover glue.. Not so pleasant since it happened during rehearsal! It is likely an easy fix, putting on a new cork and adjusting the key work, but do take it to your favorite tech since it is important that everything is nice and balanced afterwards.
 

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Assuming the linkage between the lever and the key is the cause of your issue:

IMO, in order to get a positive action and reliability in this linkage:

The two flat surfaces, when key and lever are at rest, should be parallel and about 0.3mm apart, just enough space for a thin, extremely tough material such as Music Center's "microfiber" synthetic leather to be glued to the key's surface. The need for toughness is because there is so much rubbing action and because the link is close to the hinges and the leverage is high, so relatively high forces are involved. The need for thinness is so that the lever does not try to scrape the "cork' off the key.
Failing that material, make it 0.4mm thickness and use 0.4mm "techcork".

If the space is larger than 0.4mm, and especially if the surfaces are not parallel, then pressing the lever tends to cut through the "cork" and/or scrape it off the surface.
Many manufacturers do a very poor job of designing this and setting it up, so the cork is destined to destruction, and the linkage may jam.
Sometimes this narrow, parallel gap can be achieved by bending the geometry of the linkage arm, the key cup arm, and the crowsfoot.

Yamaha has got this more wrong than most manufacturers, and incorporate techcork that is 8-10 mm thick.
So on the key's flat surface I reduce the gap by (tin/silver) soldering a small strip of sterling silver, about 0.4mm thick, onto that surface. Then there are no more problems for the life of the instrument.
On some instruments with a severe wedge-shaped gap, I resort to building up material in that gap with a wedge of sterling silver.

An ideal:
Consider two meshing gear cogs and how smoothly they interact, with minimal rubbing/wearing action. Now imagine all the teeth except one were removed from each of the cogs. Those two remaining teeth would still interact very smoothly. THAT is how this linkage should really be designed. I have seen it only in a rather obscure model of clarinet. Obviously there was an astute mechanical engineer in that factory. I was impressed!
 
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